The invention relates to a method for producing a piston ring.
It is known in general that the running surface of the ring is recessed on one side, or fully recessed, so as to improve the scraping action, in particular of compression piston rings. It is likewise generally known that chrome layers are applied to the running surfaces of compression piston rings provided with recesses.
WO 2008/098534 A1 discloses a piston ring, comprising a main body that has a running surface provided with a recess, an upper and a lower flank face, and an inner circumferential surface. At least one PVD (physical vapor deposition) coating layer is applied to the running surface, so that, in the finished state, the main body comprises the coating layer only on the edge region side, which is to say outside the recess. Here, in the region of the edge, it is possible for the relatively hard PVD layer to chip during operation, whereby the scraping action of the edge is reduced.
DE 10 2006 046 915 B3 discloses a piston ring for internal combustion engines, in the form of a base, in particular made of steel or cast iron, with a wear protection coating made of a periodic multi-layer system, wherein each periodicity consists of at least two individual layers made of metal nitrites.